Superhealing Drug Travels in Nanoparticles to Wounds

Below:

Next story in Science

A new topical medicine suspended in nanoparticles could
dramatically quicken the time it takes wounds to heal,
researchers say.

The medicine could be used to speed the healing of all sorts of
wounds, according to the researchers who are developing it.
Applications could include everyday cuts and burns, surgical
incisions, and chronic skin ulcers, which are a particular
concern for the elderly and people
with diabetes.

The medicine was tested on mice, which have a
wound-healing process very similar to that of humans,
according to study co-leader David Sharp, a professor of
physiology and biophysics at Albert Einstein College of Medicine
in New York. Sharp said he hopes to test the therapy on humans
soon.

The work appears online this month in the Journal of
Investigative Dermatology.

Wound healing is a complex process that involves moving a diverse
group of cells and molecules to the source of injury. Even a
small skin wound can take weeks to completely heal, from initial
blood clotting and scabbing to tissue regeneration and scar
formation.

Sharp and his colleagues had previously discovered that an enzyme
called fidgetin-like 2 (FL2) interferes with healing by slowing
the migration of various cells to the wound. FL2 acts to sever
structures called microtubules, which are microscopic tubes
within cells that provide cell structure and also a platform for
transport among cells. FL2 may help to prevent abnormal tissue
growth, but its complete function is not well known.

The researchers said they figured that temporarily inhibiting FL2
would enhance wound healing, so they crafted a drug to suppress
the enzyme. This drug uses molecules of "silencing RNA," to turn
off the gene that makes FL2.

In a test of cells growing in a lab dish, this drug resulted in
skin cells migrating more than twice as fast as normal. However,
if applied directly to a wound, the drug would rapidly degrade in
the extra-cellular environment before it had a chance to block
FL2.

This prompted the researchers to protect the drug, placing it in
a
nanoparticle gel to ferry it deep into the cells that needed
it. The nanoparticles are about 50 times smaller than a human or
mouse cell.

When applied to mice with cuts and burns, the nanoparticle
therapy reduced the healing time by half, the researchers found.
Sharp said that in a few months he hopes to test the therapy on
pigs, whose skin resembles humans' even more closely.

If all continues to go well, FDA approval for human use might be
possible within a few years, Sharp told Live Science. The
approval time for topical medications is usually shorter than it
is for oral medications, he said.

Nevertheless, the new drug may have potential for
internal healing in addition to its use as a topical
treatment.

"We're finding that skin is just the tip of the iceberg," Sharp
said. "We've carried out pilot studies showing that FL2 can be
targeted to promote regeneration of heart tissue after myocardial
infarction and neural regeneration with recovery of function
after peripheral nerve or spinal cord injury. These findings
underscore the potent therapeutic potential of specifically
regulating fundamental components of the cell's machinery to
protect cellular viability and promote healing."

A group of researchers in India has developed a similar
nanoparticle therapy that delivers silver nitrate, an
antimicrobial agent, to burns without the typical side effects of
silver nitrate, such as skin discoloration and damage to
surrounding cells. This reduces the risk of infections and thus
quickens healing.